Air cleaner



June 6, 1950 L. J. LECHTENBERG AIR CLEANER 2 Sheets-Shee t 2 Filed Dec. 18, 1947 Patented June 6, 1950 AIR CLEANER Leo J. Lechtenberg, Milwaukee, Wis., assignor to Briggs & Stratton Corporation, Milwaukee, Wis., a corporation of Delaware Application December 18, 1947, Serial No. 792,420

6 Claims. (01. 183-15) This invention relates to air cleaners and refers particularly to carburetor air cleaners of the oil bath type in which the air to be cleaned first impinges a body of oil or other suitable fluid and then passes through a filter maze.

Air cleaners of this type usually comprise a housing or casing formed jointly by a pair of axially separable complementary cup-like sections having their open ends substantially telescoped together to enclose a filter maze in the upper portion of the housin'g above the oil bath which is contained in the lower se'ctibn.

It is customary to mount cleaners of this type in an upright'po'sition with the bottom of the lower casing section resting on a vertically disposed carburetor inlet duct and with the discharge port for cleaned air in the bottom wall of the lower casing section communicatin with the carburetor inlet duct.

It is of course essential that the air cleaner be firmly held down onto the carburetor, and

' generally the means employed for this purpose also serves to hold the complementary casting sectionstogethen A tension screw anchored to the carburetor and passing axially through the air cleaner with'a wing nut threaded on the upper end thereof is ordinarily used. The transmission of the" clamping force, resulting from tightening the nut, down onto the carburetor inlet duct without settin up distorting stresses in the casing sections has always been a problem. In the oopending applications Serial Nos. 589,197 and 397,825 (now 'Patents 2,459,428 dated January 18, 1949, and 2,431,329 dated November 25, '1947, respectively) several ways of carrying the clamping pressure to the carburetor inlet duct without entailing distortion of the casing sections are illustrated.

While the expedients there shown perform this function satisfactorily the structures employed are somewhat involved and costly. Hence, it is an object of this invention to provide a simplified and less expensive way of transmitting the clamping pressure to points where it is needed. 7 I

Another object of the present invention resides in the provision of a simple and elficient air cleaner of the character described which may be constructed from relatively few inexpensive stampings'an'd whichmay be manufactured and assembled at low cost.

Still another object of thisinvention resides in the provision of an'air. cleaner which may be readily adapted "to either updraft or downdraft carburetors.

With the above and other objects in view, which will appear as the description proceeds, this invention resides in the novel construction, combination and arrangement of partssubstantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate one complete example of the physical embodiment of the invention constructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

Figure 1 is essentially a longitudinalsectional view through the air cleaner of this invention, portions thereof, however, being shown in elevation. i

Figure 2 is an exploded perspective view of the frame work of the cleaner cartridge;

Figure 3 is a horizontal section'through the air cleaner along the plane of the line 33 in Figure 1;

Figure 4 is a vertical sectional vie-w through the side of the air cleaner to illustrate a modification' of one of its details;

.Figure 5 is a detail cross-sectionalview on the. plane of the line 5-5 in Figure 4; and

Figure 6 is a side view of the air cleaner of this invention, portions thereof being shown broken away, illustrating its application to an section.

updraft carburetor.

Referring now to the accompanying-drawings in which like numerals designate "like parts throughout the several views, the numeral 5 designates generally the casing or housing of the air cleaner of this invention and which comprises an upper cup-shaped section 6 and a lower cupshaped section I having a rim 8 f. somewhat smaller diameter than the rim 9 of the upper The two housing sections have their open ends opposed and telescoped; together to provide an annular air intake duct l0 between their rims.

The lower casin section I has a central standpip'e'll projecting up from its bottom wall [2 and opening therethrough so as to provide the lower end portion of an exit duct 5 l 3. for the discharge of cleaned air, and an annular reservoir for a body of oil or other suitable liquid. The oil depth is maintained at a level slightly less than the height of the standpipe, the upper The filter cartridge, indicated generally by the numeral it, is permanently assembled in the upper casing section a and comprises a cylindrical shell or sleeve provided at its top with an annular flange 18, the down turned peripheral edge of which is press-fitted into the skirt of the upper casing section 6. This shell or sleeve I1 is smaller in diameter than the lower casing section 7 and extends down into the section. I a substantial distance to terminate just above the oil level. The annular space between the shell ii and the side of the lower casin section thus provides an air passage which directs the incoming air against the surface of the oil bath.

The lower edge of the shelltll. isturnedin to provide an annual ledge iS'and confined'between this ledge and the under side of the top wall 6' of the upper casing section is acspider-like framework comprising a plurality of spacing struts 2!.

The spacing struts 2! (see Figure 2) are formed by three identical stampings, each of which has a pair of substantially fiat trapezoidal arms 22 and 23 extending radially, one from either side or a central arcuate hub segment 2%. The trapezoidal, arms are cut out to allowv free flow of air through the maze oijfilter material 25 which fills the space betweenthe shell Friend the cylindrical duct formed conjointly bythe arcuate segments 24. The outer'marginal edge portion: of the arm- 23 of each stamping is bent over at an acuteangle to formza flange 26 which hooks over the outer edge 2'5 of the adjacent arm 22 when the. three stampings are assembled.

Upon assemblyof the stampings their arcuate segments ztcooperate to .forma completeicyl" inder which defines the inner wallof the annular filter cartridge anda-central tube through the filter cartridge. Since eachvstamping has two trapezoidal arms and since the abutting arms of each pair. of. adjacent stampings. together form one strut thererare. asm-any struts radiating-from the centralcylinder as. there .are stampings; and as will be readily seen the extremities of the struts 2i abut the inner surface of the cylindrical shell it to retain the central tube and strutassembly in place therein.

The filter maze 25 isconfined at the. top and bottom by upper and lowerescreens 28. and 25 respectively. Each of the screenssis annular, the upper screen being essentially conical to follow the slope of the upper edges of the struts 2i and define an air space 3t above the filter maze, and the lower screen being flat and .having its peripheral edge portion resting on theledg idol the shell ifiybeing gripped-between this fiangeand the outer portiono-f the lower edgeof eachstrut 2 i. A tube 3! having an outwardly turned flange 32 at its bottom telescopes into the central tube defined by the arouate segments. 2-4 and grips the inner marginal edge of the lower screen 29 between its flange 32 and the innerendsof the lower edges of the struts 2i.

Similarly the upper'screen 28 has'its outer marginal edge gripped between theradially outer portions of the top edges of the struts:2l and the top wall 6 of the upper casingse'ction." An upper telescoping tube33 having three outwardly turned lugs 36 at its top one above each strut 2i telescopes downwardly intocthe lower tube 3 i. To provide stiffness fcrithe inner marginal edgeof the upper screen it1has a. downturned flange 35 which is received between the arcuate segments and the upper. telescoping tubev 33, the thickness of the screen being substantially equal tofthe wall thickness of the lower tube.

The telescoped tubes-3i. and33. are presszfitted there is no centering engagement between the tube 3i and the standpipe.

To hold these parts axially aligned and return the upper and lower sections of the-air cleaner properly centered, a

--plurality of indentations are formed in the side wall of the lower-casing section I to engage the shell H.

An alternative method of centering the separableparts is shown in Figures 4 and 5. In this case a number of radially projecting arms 3'? extend from the rimof the. lower casing section to have engagement with the skirt of the upper section.

The air-cleaner of. this invention is normally assembled onto a carburetor intake duct having I an outer diameter such that it'willfit snugl inside the standpipe H with itstop abutting the in-turned flange l4 thereon. The. customary tie rod 38, which has itSvlOWGI' end anchored to the carburetor air ductin .the usual manner, ex-

tends upwardly axially. through the air exit duct l3 and passes out ofthecasing'through an aperture 39 formed centrally in the-top wallfi of the upperv casing section. .A wing nut' lfi threaded on theupper end-of the tie rodzbears against the top willof the upper casing; section .to. firmly hold the cleaner assembled on the carburetor inlet duct.

The top wall 6' is stiffened by the concentric steps formed therein sox-that, the clamping pressure exerted" by thewing nut will'beimparted to the radially outer endsof. the struts 2i with little or no deflection. of the topwall. From these points the: clamping forceis carried throughithe v spider-like. frame com-posed of .thestruts 2.! :di

rectly down onto. theannular. flange 32 which rests on the gasket IS. The gasket is thus firmly clamped between the flange 3.2and the flange l4 atthe top'of the standpipe H with the result'that the juncture between the upper'and lower sections of the exitduct l3'is tightly sealed to preclude oil ladenair being drawn therethrough and bypassing the ifilterxmaze. .-Inaddition .theqair cleaner is firmly held down ontothe. carburetor air inlet, and no distorting stresses are set up in the casing sections.

In operation the air entering the cleaner-first flows upwardly through .theannular intake l0 and thence downwardly between the side wall of the lower casing section. and the shell I! of the filter cartridge to impinge the oil 'bath'which takes much of the-dirt and: foreign matter out of'the air, and then through the filter maze where the oil and remaining-dirt is extracted. Upon leaving the filter maze the cleaned air enters the upper open end of the central air exit duct l3 through which itfiows downinto the carburetor.

As shown in Figure '6 the": air cleaner of this inventionalso may bevreadily adapted. "for; use with an updraft carburetor byzprovidingan. enlarged aperturedl in'the centerrof the closed top 8' of the upperncasing'member section, anda flanged cover plate: 42 to close the mouth'of the air exit duct. The aperture 4| openst'into'zlthe carburetor intake, and a ridge 43 on the top of the upper section fits into the mouth of the duct to hold the air cleaner concentric therewith. A hole in the cover plate 42 allows a tension screw M to pass therethrough and be threaded into a boss 45 on the carburetor intake duct. The tension screw, like the tie rod 38, draws the sections of the air cleaner together and holds the entire structure firmly on the carburetor air inlet.

From the foregoing description, taken together with the accompanying drawings, it will be readily apparent that this invention provides a simple and efficient carburetor air cleaner of the oil bath type, and that the way in which the spiderlike framework of the filter cartridge is formed from a number of simple identical stampings greatly reduces the cost of manufacturing the cleaner.

What I claim as my invention is:

1. In an oil bath type air cleaner for carburetors, interna1 structure defining a filter unit and the upper portion of a central air duct comprising: a plurality of identical stampings each having a hub segment and an arm extending radially outwardly therefrom, said hub segments being of a size such that when arranged serially side-by-side they collectively form a tubular hub to provide the upper portion of the central air duct; screens extending across the top and bottom of the spaces between the arms; filter material between the screens and the arms; and an imperforate wall encircling the arms and the filter material therebetween and holding the stampings together with their hub sections arranged serially side by sidetand facing the upper portion of the central air duct, said encircling wall cooperating with the tubular hub to close oif air flow into and from the filter material except through said screens.

2. The structure set forth in claim 1 further characterized by the provision of means providing connections between the imperforate wall and the peripheries of the top and bottom screens by which the peripheries of the screens are held against the arms; and means providing connections between the tubular hub and the inner marginal edges of the top and bottom screens by which said inner marginal edges of the screens are held against the arms.

3. The structures set forth in claim 2 further characterized by the fact that: the last named means comprises a pair of telescoped tubes fitted into the tubular hub from opposite ends thereof; and out-turned portions on said telescoped tubes overlying the inner marginal edges of the screens.

4. The structure set forth in claim 1 further identified by the facts that the imperforate wall is higher than the tubular hub, that the top edges of the radial arms slope inwardly and downwardly from the top of the imperforate wall to the top of the tubular hub, and that the top screen rests on the top edges of the arms so as to be essentially concave.

5. As an article of manufacture, a combination thrust carrier and duct forming segment for use in an air cleaner, comprising: a stamping having an arcuate segment and a flat strut extending radially outwardly from each side edge thereof, each of said struts being substantially trapezoidal in outline and. having its central portion cut away; and a hook-like portion on the outer extremity of one of said arms bent inwardly away from the other arm.

6. In an oil bath type air cleaner having upper and lower cup-shaped sections: means carried by the lower cup-shaped section and defining the lower portion of a central air duct for the cleaner; means defining the upper portion of said' air duct; a plurality of arms integral with said last named means and radiating therefrom; means securing said arms in the upper cupshaped section so that the upper portion of the air duct is carried by said upper cup-shaped section, said means including an imperforate shell fixed to the upper casing section and engaged around the outer ends of Said arms, and means at the bottom of said shell engaged under the bottom edges of the arms to hold the upper edges of the arms against the underside of the upper casing section so as to provide for the transmission of downward force applied to the top of the upper cup-shaped section onto the radiating arms whereby such downward force is transmitted, through the arms, directly to the duct forming the upper portion of the central air duct; and sealing means between said upper and lower duct sections adapted to be placed in compression by downward force on the radiating arms.

LEO J. LECHTENBERG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,240,131 Gibbs Sept. 11, 1917 2,431,329 Jacobi Nov. 25, 1947 

